ESTIMATION OF RADIATION DOSES FROM ABDOMINAL COMPUTED TOMOGRAPHY SCANS.

Abstract

A total of 120 adult female and male patients randomly selected from 10 hospitals in the West Bank and Gaza Strip were investigated for organ and effective doses from abdominal computed tomography scan. The organs considered in this study are liver, stomach and colon. Assessment of radiation doses was performed by using a commercially available Monte Carlo based software VirtualDose™ CT, a product of Virtual Phantoms, Inc. The software utilizes male and female tissue equivalent mathematical phantoms of all ages and sizes from new born up to morbidly obese patients. The corresponding phantom was selected for every patient according to patient's demographic parameters. Patient demographic data, scanning parameters and dose indicators (including patient body mass index (BMI), milliampere-second (mAs), X-ray tube kilovoltage (kVp), computed tomography dose index (CTDIvol), dose length product (DLP), manufacturer, name and type of operated CT scanner) were recorded for every examination. The collected parameters were used to calculate the organ and effective doses for every patient. The highest estimated patient organ doses were 25 mGy for liver, 20 mGy for stomach and 30 mGy for colon for a male patient with BMI of 30 kg/m2 and 90 kg of weight. This patient correspondent effective dose was 9 mSv. The average effective dose for the entire patient population was 5.5 mSv with a range between 2 and 10 mSv. The highest effective dose was found for a female patient with a BMI of 26.6 kg/m2, and 77 kg of weight. This patient correspondent organ doses were 14, 9 and 14 mGy for the liver, stomach and colon, respectively. The average organs doses per patient estimated for patients from all investigated hospitals were 13.1, 7.6 and 13.2 mGy for liver, stomach and colon, respectively. Both effective dose and organ doses increase with BMI and body weight. In general, the estimated radiation doses from abdominal CT examinations in this study are low and comparable with those published in the literature.